Thread by @sophusticated

Our (@DICE_Kent @wildbusiness & team) evaluation of England's biodv compensation policy 'Biodiversity Net Gain' is out in @ConLetters, adding to academic lit evaluating outcomes of biodv compensation systems conbio.onlinelibrary.wiley.com/doi/full/10.11…. Takeaways for academic #offsetting peeps: 🧵

This adds to the relatively few jurisdictional evaluations that use real data, such as Gibbons et al. 2018 for New South Wales onlinelibrary.wiley.com/doi/abs/10.111…, & classic work in Canada by Quigley & Harper link.springer.com/content/pdf/10…

The evidence surrounding compensation systems is getting better; there have been 3 quantative reviews of outcomes in the last few years. 1 by @theis_seb conbio.onlinelibrary.wiley.com/doi/abs/10.111…; 1 by Josefsson et al. sciencedirect.com/science/articl…; 1 by us conbio.onlinelibrary.wiley.com/doi/full/10.11…

So, key takeaways for academics. 1) Metrics. The Biodv Metric used in Net Gain is simple, easy to use for non-specialists, non-replicable, & severely open to judgement-based variability. It's not been empirically evaluated in the field, so that's a huge gap.

I worry we're heading towards smtg shown by @RobertsonMorgan & co, where Metric becomes the be-all-end-all, crowding out ecological complexity & other biodv info journals.sagepub.com/doi/abs/10.117…. Have seen several biodv-harming developments justified now cos Metric shows an 'improvement'

2) Governance. We show there are enormous governance gaps in Net Gain that could really harm enforcement & compliance incentives - things @megcevans warns about in her work & thesis openresearch-repository.anu.edu.au/handle/1885/13…; & Quetier et al. show for France too sciencedirect.com/science/articl…

Can't encourage peeps enough to read Damiens @Ascelin @LibbyJPorter's paper here: sciencedirect.com/science/articl…. If the governance isn't solid, then compensation systems can harm us today without necessarily compensating in future, & whole logic of offsetting breaks down

3) Avoidance. It looks like Net Gain *might* be incentivising development on less ecologically valuable land - as predicted by @TopcatToni & team here: sciencedirect.com/science/articl…. Although, we need to compare avoidance before & after Net Gain to be sure, & that's very tough.

4) On-site vs off-site. Although Net Gain is often viewed as an 'offsetting policy', our data shows it's more of an 'onsetting policy' - 95% of biodv units delivered 'on-site' or right next door. Could be a real-world test of onsetting ideas of @sbekessy @M_Selinske & team.